Loki is better than Kaido in every way. It is what it is.
Adult Kaido bled from a casual kick from Rocks, child Loki took a two handed AdCoC sword strike from Rocks and did not bleed
Fruitless Loki clashed evenly with Harald before outright surpassing Harald by overpowering Ragnir, hybrid Kaido needed alcohol to surpass gearless adcoc Luffy
Loki’s Devil Fruit was hyped as a fruit that could end the world by multiple sources including Rocks, Kaido’s fruit was hyped as a fruit worthy of Perospero by Big Mom
There really isn’t a comparison, Loki is completely superior to Kaido in all regards.